This invention relates generally to lasers, and, more particularly to a floating head mirror assembly for use within the optical or resonant cavity of a laser.
The development of the laser has created a new area of technology which finds application in many systems already in existence today. For example, lasers can be found in the area of optical communications, holography, medicine, cutting, calculating and in radar. The utilization of the laser in such areas is in many instances dependent upon the amplification of the existing laser radiation.
In certain areas, such as in optical communication or optical radar, it is necessary to greatly amplify the initial radiation power produced by the laser. One such laser which produces high output power is the cylindrical chemical laser. In such a laser, or in most conventional lasers, the "optical or resonant cavity" of the laser typically comprises plane parallel or curved mirrors located at right angles to the axis of the cylindrical region. The cylindrical region may be a gas envelope or the like in which lasing action takes place. For laser operation, one of the mirrors is required to be partially transmissive in order to extract a useful beam of coherent light from the "optical cavity."
It has long been recognized that the alignment and optical figure of the mirrors of the laser are of critical importance in order to maintain maximum output. Frequently, laser mirrors after being correctly aligned, particularly mirrors used in chemical lasers and gas dynamic lasers, are exposed to such intense light as to be subjected to radiative absorptive heating even with the best reflective surface. Such an environment causes substantial misalignment and distortion to the mirror. High power laser mirrors (greater than 5 Kw/cm.sup.2 light intensity) tend to distort due to the heating of the reflective surface.
It is essential, however, that such surfaces be held within four micro-inches on DF lasers. When the mirror surface is heated, the lower base surface to which the mirror is attached generally remains at the starting temperature and as a result causes an output shearing force between the mirror surface and the base structure. This shear rotates the outer perimeter of the mirror. At present, the mere cooling of the mirror itself fails to overcome this problem. Consequently, as the high power requirements for the lasers increase, the difficulties of matching high power laser mirrors to the laser output requirements have become an expensive and sometimes virtually impossible task.